1. FIELD OF THE INVENTION
The present invention relates to hardware for mounting printed wiring cards and more particularly to novel card file assembly adapted to facilitate the placement of printed wiring cards employing current packaging methods into existing frame hardware designed to accommodate an older technology.
2. BACKGROUND ART
At the present time, large computing facilities or telephone central office systems are generally constructed with a number of hardware frames adapted to receive substantial quantities of printed wiring cards. Electrical functions or sub units are provided in increments of such card files mounted in equipment frames. It has been found that implementation of new technology into existing electrical functions is typically provided in new production only. Adaptation of these newer technologies to field implementation is often extremely difficult to accomplish due to substantial mechanical differences particularly as to differences in mounting space between old and new technology hardware.
Where electronic circuitry is incorporated in products which have been in production for a substantial number of years, the amount of technological change over the years can be extremely large. Usually the only way that customers or users of the newer technology receive the benefits of new technology is by ordering new equipment providing additional frame space to mount such new equipment. This latter is the usual case, particularly since existing field locations do not receive the benefits afforded by the newer mounting technologies. Accordingly, it is the object of the present invention to provide a card file design that fits within the envelope size of existing card files. By incorporating new side plate designs it is possible for such provision to allow customers and users to upgrade existing electrical functions to newer technology without encountering many of the pitfalls or difficulties frequently encountered in such situations. The arrangement presented also provides the additional feature of being able to add a completely new function to the unit by utilizing the spare card files of the older technology.